Very often, the answer to this question is No. Good sets of local election results for the Conservatives in 2000 and 2004 were followed by big defeats in general elections the following year. More specifically, seats where a party has a big lead in local elections one year, may produce an equally big lead for another party at Parliamentary level. To take one example, the Liberal Democrats have been a strong force in Liverpool local government since 1973, yet have largely failed to transform that into success at Parliamentary level (David Altonâ€™s success notwithstanding).

There are several obvious reason for this. Firstly, people split their votes in different types of election. The same voter might vote Liberal Democrat at local level, Labour at Parliamentary level, and UKIP at European level, for example. It is clear, likewise, that lots of people who vote Conservative in Wandsworthâ€™s local elections, will have voted Labour in the last three general elections. Secondly, an incumbent MP can build up a level of popularity that outweighs that of their party locally. Gisela Stuart, for example, is popular in Edgbaston, and held her seat in 2001 and 2005, notwithstanding that the Conservatives generally lead by 20-25% in local elections in her constituency. Thirdly, local elections are usually held at different points in the electoral cycle to general elections. A proportion of voters will use local elections as a means of protesting against the government of the day, or will stay at home, before going out to vote for that government in a general election.

However, local elections cannot be dismissed as entirely irrelevant to Parliamentary contests. Sometimes, they do point to long-term shifts in political allegiance at every level.

One example of this is the London overspill towns and estates, which were, for many years strongly supportive of Labour. In recent years, however, towns like Hatfield, Borehamwood, Crawley, Hemel Hempstead, and Harlow, have shown marked shifts away from Labour, which were backed up by big swings to the Conservatives at the 2005 general election. Such towns had shown considerable support for the Conservatives at Parliamentary level, in the 1980s, while continually voting solidly for Labour at local level. In the future, they can probably be regarded as Conservative in anything other than a bad year. Likewise, the collapse in Conservative support in the 1994 local elections, in places like Streatham, Hornsey and Wood Green, and Croydon North, pointed to a permanent shift in outlook among the voters in those places.

All parties depend on local councillors to keep going in many places. A local party can probably survive the occasional heavy defeat at local level, and keep its organisation going, but when it is beaten year in and year out in local elections, its activists will tend to drift away. At the same time, the voters will have got into the habit of voting for its opponents. There are quite a few parts of the country where one party was dominant for many years, and where there now seems to be no way back for it.

Last nightâ€™s by-election results were generally quite good for Labour, although there were some unusual local circumstances.

Sandwell MBC, Charlemont/Grove Vale. Conservatives 870, Labour 801, BNP 544, Liberal Democrats 238,Greens 71. Conservative hold. On the face of it, this shows a strong swing to Labour, compared with May. However, the outgoing Conservative councillor had been found guilty of a serious criminal offence, and the Conservatives actually did rather well to hold this.

Nuneaton & Bedworth DC, Slough. Labour 862, BNP 582, Conservative 499, English Democrat 102, Liberal Democrat 83. Labour gain from Conservative. The Conservatives won this ward in 2004, but Labour won it in 2006. This was still a very good result for Labour, and a very good result for the BNP also.

Wigan MBC, Tydesley. Liberal Democrat 784, Labour 619, Independent 377, Conservative 170. Liberal Democrat hold. This showed a huge swing to Labour, compared with May. However, it must be pointed out that the outgoing Liberal Democrat councillor had been disqualified, and the victorious Liberal Democrat had just finished a period of disqualification. In the circumstances, the Liberal Democrats probably did well to retain the seat.